Menstrual angina

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Women with heart disease are more likely to have severe symptoms and possibly a heart attack at the beginning of their monthly cycle, according to new research from Britain.

Researchers from the Cardiothoracic Centre report in the journal Heart, the first study to quantify 'menstrual angina', a phenomenon where angina is more likely to be suffered in the week during or immediately after the period.

The research adds further to understanding the key role that female sex hormones play in a wide range of functions. Research has already shown that the time of the month can profoundly affect the symptoms of migraine, asthma and cardiac arrhythmia.

Angina is a heavy, squeezing chest pain which occurs when not enough oxygen gets to heart muscle. It is common in patients with a history of heart disease.

The researchers studied the blood hormone levels and heart activity in nine women patients in their late 30's with a history of heart disease during all phases of their cycles. Four of them had already suffered a heart attack, and one had undergone bypass surgery. To get an idea of how well their hearts were fairing, participants used an exercise treadmill while their heart was monitored.

The early follicular phase - the week during or immediately after a period-produced the worst exercise performance and the quickest time to angina pain: 290 seconds. This phase is when levels of the sex hormones oestrogen and progesterone are lowest. The best performance and slowest time to angina pain, of 418 seconds, occurred in mid-cycle, when oestrogen concentrations peak.

Previous studies have shown the oestrogen is a vasodilator - it relaxes blood vessels and allows blood to flow more freely. Because of this, oestrogen has been implicated in reducing the risk of heart disease and heart attacks. Indeed, it is thought that heart disease is rare before menopause, partly owing to the protective effects of oestrogen in the blood.